The problem of addressing to a group of persons or stations according to their geographical position or interest may arise in many situations, and has been addressed in different manners.
Classic radio solutions exist for talking to several vehicles, such as taxis in a town. For talking to taxi drivers that are near a specific place, a central operator may give a general voice call with the name of the place, and only concerned drivers answer to the call. In order to avoid many drivers receiving a call for a place they are not near enough, different channels may be defined related to different zones. Each driver then tunes its receiver on the channel he is entering or interested in, but he has to know the identification of each of these channels.
Computerized solutions have been proposed, which may automate such knowledge and tuning, and sometimes use IP multicast technologies such as in WO03040972. However, receiving stations still have to be customized for memorizing different channel identifications, and update such identifications as time goes by. Also, deploying and maintaining such a data infrastructure network is something quite complex, costly and time consuming. Moreover, known techniques for IP multicast data frames are not always adapted to specificities of geographical groups or mobile receiving stations, while reducing or optimizing data traffic on such a network is always a matter of interest.